license file(s) always disapearing

Hello,

in my quartus II 12.1 Build 243 my license file(s) are always disapeared on restart the software. Then I have always hard to search and reenter all license files.

The license files are on the local hard disk as follows: C:\altera\12.1sp1\license\1-xyxyxyx_License.dat

Thanks for all help